Long Term Evolution (hereinafter referred to as LTE) is a next-generation mobile broadband network standard defined in the Third Generation Partnership Project (3GPP). Orthogonal frequency division multiplexing (OFDM) is used and the multiple in/multiple output (MIMO) is introduced to simultaneously support 1.25-20 MHz bandwidth, greatly increase the peak data rate and system capacity, and support peak rates of downlink 100 Mbit/s and uplink 50 Mbit/s in the 20 Mhz bandwidth; the flat network architecture enhances the scheduling and radio resource controlling efficiency and shortens the connection delay.
The multimedia broadcast/multicast service (MBMS) has been supported in the third generation mobile communication systems, and the Enhanced Multimedia Broadcast/Multicast Service (eMBMS) designed in the fourth generation mobile communication LTE system is a service with strong applicability in the industry. Its implementation is that an intelligent terminal with video capability receives a digital audio/video service in the form of broadcast/multicast through the physical multicast channel (PMCH). For the eMBMS implementation and networking, the 3GPP protocol standard provides a complete solution.
The Consultative Committee on International Radio (CCIR) names the trunking communication system as “Trunking Communication System”, and China translates the Trunking Communication System into “trunking mobile communication system”, which is often referred to as trunking communication system or trunking system.
The trunking communication system is designed and developed to meet the users' commanding and scheduling needs in the industry, and is a dedicated wireless communication system for industry-specific applications, the wireless users in the system can share the wireless channels, and commanding and scheduling are taken as the main applications, it is a versatile and high-performance wireless communication system, and has unique group call capability and the feature of fast call, the group can be a single call or a group call, and the single call refers to that the group only has two users, while the group call is that there or more users are within the group. The trunking communication system has the following characteristics compared to the public cellular mobile system:
(1) fast call connection;
(2) the users within a group call share the downlink to multicast receive;
(3) it is the half-duplex communication PTT (Push To Talk) within the group, and a user having the uplink is the user having the talking right in the group, otherwise, the user is a listening user in the group;
(4) support private call and group call;
(5) when calling and speaking, it needs to press and hold the PTT key, and the called does not need to hook.
The trunking communication systems have a wide range of applications in government departments, public securities, emergency communications, electricity, civil aviation, petrochemical, military, and other fields. With the economic development, leasing, logistics, property management and plant manufacturing also increasingly need the trunking communication.
The trunking communication system will also technically develop in the direction of IP system, diversified services, data broadband, and multimode terminal. From the perspective of specific applications, it mainly embodies in the high-speed data, video, and a variety of applications built on this basis.
Therefore, the trunking communication system needs to have larger channel capacity, higher spectrum efficiency, better transmission performance, and with low-cost, scalable, and configurable all-IP wireless multimedia network architecture, it can achieve smooth evolution. The trunking communication is becoming a major dedicated communications system besides of the public mobile communication.
However, as the fourth-generation mobile broadband LTE system, there is no existing solution for trunking communication service.